Simon Hills gives his reaction to the House of Commons voting, on the back of junk science, to ban smoking in cars when under 18s are present - suggesting it's only a matter of time before our homes are next

So our politicians have finally crossed a rubicon in passing legislation banning adults from doing something in their own private space on the grounds that they don't approve of it. Smoking is to be banned in cars if there are children in the vehicle. Writing an article for The Times about the proposal, the columnist Gaby Hinsliff wrote: "There's little point arguing this one out with hardcore libertarians, although it beats me why anyone would fight for the right to give their children cancer."

This was the headline for the piece: "Who would fight for the right to give kids cancer?" This is the same as writing, surely, "Who would fight for the right to give kids a paralysing spinal injury?" for those parents who might want to take their children horse riding. Or, "Who would fight for the right to let their children freeze to death?" for those who take them walking in the Cairngorms.

In fact, despite the demonic, despotic science on the effects of secondary smoking, there has been the most pitiful evidence that it has done any children any harm at all.

Look at the generation who secondary-smoked more than any other, the children of the Forties and Fifties. They snorted second-hand smoke on the tops of buses, at their aunty Joan's, their friend Shona's and in the hairdressers. They secondary smoked in the back of Jaguar Mark IIs with ashtrays the size of Hertfordshire, and secondary smoked in seafront cafés in rainy Blackpool. Secondary smoking was obligatory at sporting events, and oh my word, how did they ever survive the cinema?

This is the generation that has the longest life expectancy ever known in the history of the human race. Indeed, if the current scare-mongering is to be believed, the non second-hand-smoking generation with a diet of doughnuts, fizzy drinks, burgers and, as they get older, a whole cocktail of legal highs are on their way to reversing this extraordinary life expectancy.

This isn't to say that second-hand smoking is a particularly to be recommended. But it surely doesn't give some Stalinist jobsworth the right to poke his head into my car and tell me to stop smoking in front of my children. My children - not the government's children. My car - not the government's car.

In my case it's unlikely that it will ever happen. But it might. If I've been stationary on the M25 for an hour and a half, I might wind the window down and try and relieve the stress with a calming Winston Light. The chance of this giving my children cancer is, I reckon, 0.00000001 per cent. But a busybody with a headcam can report me to the plod and I can expect a fine at best, and who knows, losing my children for such cruelty. So I won't. And I shall be very, very, very cross instead. And my children will be unhappy.

This, though, is the priggish, self-righteous, self-deluding age we live in.

And what is so disturbing, is that it is based on wilfully erroneous science.

Science used to be about rigour. Before any hypothesis was accepted as scientifically sound, the obverse had to be proved incorrect. Fat chance now. Science is a politically-motivated, grant-seeking art that survives by expounding the most outrageous claims and cobbling together a few computer projections to 'prove' the point. (Projections on crime for example that would have us all in prison on 50 years time; if we're not all dying from third-hand smoke trapped in the curtains of ancient hotels.)

Did you know that fizzy drinks and fruit squashes are linked to depression? Severe air pollution "can double the risk of having an autistic child"? Sitting down for up to seven hours a day puts women at greater risk from type two diabetes? Eating junk food reduces a man's sperm count? And on, and on, and on. Meaningless random studies that are churned out daily that keep so many thousands of people in work.

This is the science of Stalin and Hitler. Science where 'facts' fit policy.

It shamefully undermines the work of Newton, Faraday and Fleming, and pretty much any scientific endeavour pre-1960; science that has bestowed upon us unprecedented freedoms because of its rigour and political impartiality. What chance of that now, in a world where science has largely been hijacked by political expediency, prejudice and self-interest? This is science that is designed to whip up hysteria in a never ending quest for headlines and concomitant funding.

Before the vote to ban smoking in cars, Luciana Berger, the Shadow Health Minister, asked MPs: "If we know beyond doubt that passive smoking in an enclosed space can do serious harm to a person's health, and that hundreds of thousands of children are being subjected to this every week, should we act and do something or do we stand by and do nothing?"

Well, absolutely stand by and do nothing. It's none of your business and, more importantly, you don't know beyond doubt. Any sentient person would only have to look consider the number of healthy septagenuarians and all their contemporaries to conclude that these politically motivated studies are suspect in the extreme. If you don't, and Luciana Berger and the other 375 MPs who voted for the ban obviously don't, then the path is clear to banning smoking in the home, fizzy drinks, fatty meat, crisps, anyone driving anywhere above 20 miles an hour, drinking over the legal limit at any time, walking while drunk... oh, go on, pick anything you like. The Hobgoblin University of Catford will have knocked up a study to prove you right and have a 'model' that tells exactly how many lives will be saved.

This dreadful decision, in other words, is a charter for politicians to boss us into submitting further to their will, whether we like it or not. History tells us that they won't be reluctant to do so.

And we should all be terrified at the thought.

Simon Hills is associate editor of The Times Magazine